Sulphurized oil



Patented Nov. 26,1940

- UNITED STATES SULPHUBIZED on.

John 0. Zimmer, Hillside, N. J.,- assignor to Standard Oil DevelopmentCompa a corporation of Delaware No Drawing. Application October 8, 1937,Serial No. 168,011

The present invention relates to sulphurized oils and to methods formaking the same. The invention will be fully understood from thefollowing description:

It has been known for many years that sulphur increased the load bearingcapacity of oils for lubrication of hypoid and other gears where high orextreme pressures may be encountered, metal working and the like andmany such oils have 10 been and 'are now used for these purposes. In

some cases mineral oils have been sulphurized directly; in others fattyoils such as lard and fish oils are sulphurized and are added to themineral bases. Both of these products serve the'purpose 15 but at thesame time have many disadvantages; for example, it is difiicult to addenough sulphur to mineral oils to give suflicient load bearing capacity,without encountering sulphur separation when the product is cooled.sulphurized 20 fatty oils containing more than 10 to 12% of sulphur havea very foul odor which is objectionable in cutting oils and the like,and if the sulphur content is reduced the extreme pressure propertiesare greatly impaired. Moreover their 25 blends in mineral oil do notpossess sufilcient extreme pressure properties for satisfactorylubrication of automotive hypoid gears, and the sulphurized fatty oil isoften not completely soluble in mineral oil and tends to separate instorage and 30 service.

Similar difficulties occur with the various other sulphurized baseswhich have been suggested from time to time.

It has now been found that these difliculties it; can be overcome byusing as the base to be sulphurized a solvent extraction product ofpetroleum. The extract is obtained by the use of solventssueh as phenol,cresol, dichlor ethyl ether, aniline, sulphur dioxide, nitro benzol,furfural, and the like, which various solvents with others, too numerousto specifically mention, make up the class of extraction solvents whichare used to separate liquid paramnic constituents from non-paraifinicfractions. The extracts may be obtained from petroleum fractions suchas.

kerosene, gas oils, and the light and heavy lubricating fractions; Thequality of the extract depends of course to some extent upon the crudefrom which it is obtained and the intensity of 0 the extractiontreatment, but for present purposes it has been found that an extracthaving a viscosity index below about +50 is suitable for the purpose,although it is preferred to use materials having a lower viscosityindex, for example be- 5 low 0, -23 or '10. or even lower. The extracts9 Claims. (01. 252-45) improved may be obtained from paralfinic,naphthenib, or mixed asphaltic base type of crude oils. In general thepreferred stocks are those rich in natural sulphur, for example theoriginal sulphur content varies from say 0.6 to 3 or 4% of the extract.5

The extract may be sulphurized by any of the convenient known methodsfor introducing free sulphur into the hydrocarbon material; For example,free sulphur itself may be heated with the extract to temperatures ofabout 325 F., but it is preferred not to raise the temperature in excessof about 375 F. to 400 F. Normal paramnic petroleum oil takes up sulphurwith difficulty. It is accomplished only under strong heating and theresulting material is not stable as has been indicated above.The'present stocks prepared from the solvent extraction products ofpetroleum sulphurize with greater ease at lower temperatures and producerelatively stable stocks of high sulphur content from which the sulphurdoes not settle on standing.

When the sulphurization is carried out with free sulphur, it isdesirable to heat the oil with sulphur to a reaction temperaturewhich'is indicated above as from about 300 F. to 375 F. or 400 F. Thereactions occurring are not entirely understood, but it is apparent thatthe sulphur enters quite readily, but on continued heating for aprolonged time, it is converted into a less active form which isundesirable. Therefore in the present case the oil and sulphur areheated to the reaction temperature for a relatively short period,usually not over two hours and frequently much shorter. Samples arecontinually withdrawn so that the heating may be discontinued as soon asthe sulphur is dissolved and forms a substantially clear solution. Whenthis has occurred, the product should be cooled rapidlg to a temperaturebelow 250 F. in order to prevent further internal reactions which leadto a loss of a portion at least of the extreme pressure capacity. Thecooling may be accomplished by circulation of the material through aheat exchanger, but it is preferable to add a part or the whole of themineral oil with which the base is to be blended in order to bring thetemperature down as rapidly as possible below 250. F. It is notnecessary to rapidly cool beyond this point.

The product made above is perfectly satisfactory, but its properties maybe further improved 60 by a second sulphurization treatment after theinitial sulphurized stock has been blended with the petroleum oil inwhich it is intended to be used. This may be carried out insubstantially the same way as indicated above and it is found possibleto further sulphurize the product and to markedly increase its alreadyhigh extreme pressure qualities. As an example of this, say 25% of thetotal sulphur required in the oil may be introduced directly intosulphurlzation while the balance is used to sulphurize the blend of thisextract with the mineral oil in which it is to be used.

Substantially the same results can be obtained in a singlesulphurization carried out in the following manner. The solventextracted oil is blended with a portion of an ordinary minerallubricating oil, for example, preferably of a parafllnic stock which hasa viscosity index above and preferably above 90. The solvent extract mayamount to from 5 to 25% of the oil to which it is added and the blend isthen sulphurized with the entire quantity of sulphur which is to beused; and which may vary from say 5% of the extract to 25% thereof. Theoperation is carried out as indicated above, the temperature beingreduced rapidly by cooling as for example by the addition of a furtherquantity of the same or some other similar unextracted petroleum oil orby circulation through a cooler or heat exchanger. The quantities shouldbe such as to leave from about 1 to 5% or more of sulphur on the finalproduct.

While it is preferred to use free or elementary sulphur for thesulphurization treatment, it will be understood that other sulphurizingmeans which are equivalent may be used for the same purpose.

It has been found that the extraction product referred to above may beused alone as the sulphurized stock, or it may be used to replace acertain amount of the fatty oil which has previously been employed. Insome instances, it is .desirable to have some of the fatty oil presentand in these cases the extraction product and the fatty oil may eitherbe sulphurized separately and mixed or may be admixed and sulphurizedtogether, for example, in proportion of say 10-75% of the extractionproduct and -25% of fatty oil such as sperm oil, lard oil, rapeseed oilor the like. The presence of the extraction product appears to greatlyincrease the ease of sulphurization and to improve the product obtained,particularly from the standpoint of freedom from obnoxious odor andimproved load carrying capacity.

The sulphurized stock and the mineral lubricating oil containing thesame may be used for many purposes. They may be employed in cutting oilsor in oils used for other processes of metal working such as stamping,drawing and the like, wherever, in fact, sulphurized oils are nowemployed, and the degree of sulphurization of the base and the amount ofthe base in the mineral oil may vary considerably depending on theparticular use to which the oil is to be placed. The stock may also beused for gear lubrication, especially for the lubrication of steel gearsoperating under high pressures, for example in the automotivedifferentials or other gear units employing hypoid or other types ofgears. For these purposes it is frequently desirable to add to the oil asoluble lead compound such as lead naphthenate or lead sulphonate, ortheir equivalents. Such materials should be added after the sulphurizedstock has been cooled to a temperature of about 175 to 180 F., so as toprevent immediate reaction of the sulphur with the lead, it beingdesired to obtain the materials in separate compounds in the final oilwhich is free from suspended solids.

the extract in the initial The oils described and produced as above haveexcellent extreme pressure qualtities which are not rapidly lost duringthe normal use of the oil which is one of the chief objections to manyof the products now available. These oils show no separation of sulphurand the viscosity index of the finished blend is not so greatly reducedby the use of a sulphurized extract as would be supposed. For example,where an unsulphurized extract is added to a mineral oil of to V. I. inquantity suflicient to give a reduction in viscosity index from 70 to75, it has been found that after'sulphurization, the same amount of theextract produced a blend of from 85 to 90 V. I. In addition, thecompounds are extremely stable during use even when subjected tooxidation. Many of the oils used at the present time oxidize so rapidlyas to become solid after a few hours of severe oxidation or in severehigh temperature gear service. These oils, however, have been found tothicken only slightly during such treatment.

In order to further illustrate the nature of the present products andthe methods by which they are made, the following examples are offered.

Example 1 A solvent extract of a light petroleum lubricating oil wasobtained by treatment with-phenol.

Its properties were as follows: v

Gravity A. P. I 15.4 Flash 450 F. Vis. 100 F 1843 Vis. 210 F 83 V. I 5Pour point 10 Percent sulphur (natural) 1.16 Cast Dark green The solventextract was heated to a temperature of about 350 F. and 5% by weight ofsulphur was added. The temperature was maintained at between 350 and 375F. for about two hours until a withdrawn sample was found to besubstantially clear. The product was then rapidly cooled to 250 F. and aparaflinic cylinder oil was added, about 19 parts of the cylinder oil to1 of the sulphurized base, and the mixture was then reheated to 350 F.at which time two parts by weight of sulphur were added, and the heatingcontinued as before to effect the reaction.

The final product had a viscosity at 210 F. of 234 seconds Saybolt and aviscosity index of 96. On the S. A. E. testing machine the productcarried a scale pull of 580 lbs. on the S. A. E. extreme pressurelubricant tester operated a 1000 R. P. M. at 14.6/1 rubbing ratio and83.5 lbs/sec. loading rate.

The product was then heated for 18 hours at 200 F. and then tested onthe S. A. E. machine at 530 R. P. M. The scale pull was found to be 580lbs. After 100 hours at 210 F. the test was again repeated using thesame machine at a speed of 530 R. P. M. and the product still carriedthe full load on the test machine.

The above was a very severe test and indicates that the product will notlose its extreme pres.- sure properties even under extreme conditions ofoperation. On heating for 100 hours at 300 F., it was found that theviscosity had increased from 234 to 275 seconds at'210 F., indicatingvery little thickening.

Example 2 Two further samples were made up according to the procedure ofExample 1 except that in these cases -7 and 10% of the sulphurizedextract was used instead of 5%, as in Example 1. Lighter mineral oilswere also used so as to give lower viscosities. These materials were:examined When these materials were tested on the S. A. E. machine at1,000 R. P. M. both showed a scale pull of 580 'lbs. After 18 hoursheating at 200 F. the test was repeated at a speed of 530 R. P.-M. andthe same scale pull was observed on both samples. After 100 hoursheating at 300 F. the samples were again tested on the S. A. E. machinewith a velocity of 530 R. P. M. and in each instance the scale pullrecorded was 580. After heating for 100 hours at 200 F., the firstsample containing the 7% extract had thick"- ened slightly so that itsviscosity was now 86.5 seconds. The second sample, however, maintainedits original viscosity of 109.2 seconds.

Example 3 In the following tests difl'erent amounts of the solventextract were used, but in each instance 40% of the unextractedparafflnic mineral oil was added to the extract before sulphurization.The sulphurization was carried out at about 350 F. and as soon as thesulphur was thoroughly dissolved the mixture had been chilled to atemperature below 250 F. The following table shows some of theproperties of the materials. Tests 1, 2 and 3 were made on the samemineral oil.

! 1 Q v r i r 1 sampes mac inc a. P. M.

1 Percent extract l l0.. 217 93 580 2 Percent extract 15.. 212 92 580 3Percent extract 20 192 92 580 4 Percent extract 15 94.5 90 580 5 Percentextract. .20 85.8 86 580 Example 4 In the table below are giveninspections and tests on two leaded oils made according to the preferredprocedure.

Grade 8. A. E. 90 S. A. E. 160 Type 15% phenol extract 15% phenolextract Gravity, A. P. I 19.0 18.7 Flash F 415 425 475 4590 212 92.0 251.97 Sediment, pcrcent Trace 0.1 Sulphur,-percent 2.3 2.4- Sulphurseparation at 0 F Nil Nil Almen shock load 15 weights 15 weights S. A.E. machine test (1000 R. P. M.) scale pull 630 lbs. 580lbs.

The above materials were made by blending 15 parts of phenol extractwith about 35 parts of mineral oil. The mixture was heated to 250 F.during agitation. and 2.25 parts of S111- phur were added. Thetemperature was then raised to 350-375 F. during the course of two hoursand at the end of this heating period it was found that the sulphur haddissolved into and permanently reacted with the 011. At this point 40parts of cold mineral oil were then added and the temperatureimmediately dropped to about 250 F. The product was then further cooledto about 180 when of lead naphthenate and about 1% of a pour pointinhibitor were added i Example 5 To illustrate the application of thebase stock to cuttingoils and to further illustrate the improvement,experiments were carried out in which lard oil, sulphur and theextraction product of petroleum were heated together to effectsulphurization at a maximum temperature of 370 to 375 F. Differentamounts of sulphur were added but it was only required to hold'thematerial at the temperature for about minutes, to eflect sulphurization.They were then cooled to below 250 F. It was found that when the lardoil was used alone with more than 12% sulphur the odor was very bad, andalthough the products were blown with air to remove sulphur and sulphitefumes, it was found thatthe odor rapidly developed again. This odorcould not be masked by addition of pine oil or other available aromaticmaterials. When equal quantities of lard oil and phenol extract wereused, it was found that considerable more than 15% of sulphur could beintroduced easily according to the procedures of the present invention,and while the odor could not be described as pleasant, it was muchbetter than the sample made from lard oil alone and was easily maskedbythe addition of small amounts of pine oil, for example, about-1%. Theproduct, whether the pine oil beused or not, is sulphur stable and doesnot show any separation when stored at zero for'l days. It will beunderstood that the sulphur is,,of course, in a highly corrosive formand shows high extreme pressure properties. v

The expression, "monohydric phenol extract, is intended to denote anextract prepared by solvent treating the desired petroleum fractionswith aromatic compounds containing, attached directly to their nuclearcarbon atoms, only one hydroxyl group per molecule. Specifically, theexpression is intended to include the use 'of phenol, the cresols, etc.

The present invention is not to be limited by any theory of themechanism of the present sulphurization process nor to the use of anyparticular ingredients, but only to the following claims in which it isdesired to claim all novelty inherent in the invention.

I claim: p

1. A composition of matter comprising a sulphurized monohydrlc phenolextract of a mineral lubricating oil fraction, said sulphurized extractbeing prepared by subjecting the monohydric phenol extract to the actionof elemental sulphur in an amount between about 1% and about 10% byweight at a temperature between about 300 F. and 375 F., followed byrapid'cooling to below 250 F.

2. A process which comprises sulphurizing a monohydric phenol extract ofamineral lubricating oil fraction with elemental sulphur in an amountbetween about 1% and about 10% by 5 weight at a temperature'betweenabout 300 F. and 3'75 F., followed by rapid cooling to below 250 F.

3. A composition 01' matter comprising a sulphurized monohydric phenolextract of a mineral lubricating oil fraction, the untreatedextracthaving an A. P. I. gravity above 9, a viscosity index between about +100and about +50, and having a viscosity at 100 F. of between about 1,000and about 5,000 Saybolt seconds, said sulhurized extract being preparedby subjecting the monohydric phenol extract to the action oi elementalsulphur in an amount of between about 1% and about 10% by weight at atemperature between about 300 F. and about 375 F., followed by rapidcooling to below 250 F.

47 A process which comprises sulphurizing a monohydric phenol extract ofa mineral lubricating oil fraction having an A. P. I. gravity above 9, aviscosity index between about 100 and about +50 and a viscosity at 100F. between about 1,000 and about 5,000 Saybolt seconds, with elementalsulphur in an amount between about 1% and 10% by weight at a temperaturebetween about 300 F. and about 375"F followed by rapid cooling to below250 F.

5. A composition of-matter comprising between about 5 and about 25 partsof a sulphurized monohydric phenol extract of a mineral lubricating oilfraction, said untreated monohydric:

phenol extract having an A. P. I. gravity above 9. a viscosity indexbetween about -100 and about and having a viscosity at 100 F. beiwicllabout 1,000 and about 5,000 Saybolt seconds, said sulphurized monohydricphenol ex- 0 tract being prepared by subjecting st 1 untreated extractto the action of elemental sulphur in an amount betweenabout 1% andabout 10% by weight at a temperature between about 300' F. and about 375F., followed by rapid cooling to below 250 F., adding between about andabout parts 0! a mineral lubricating oil containing 5 at least a smallportion of unsaturated compounds and subjecting the resulting mixture tosulphurization with elemental sulphur in an amount of between about 1%and about 5% by weight at a temperature between about 300' F. 10 andabout 375 F., iollowedby rapid cooling to below 250 F.

6. A sulphunzed mixture comprising between about 5 and about 25 parts ofa monohydric phenol extract of a mineral lubricating oil Irac- 1 tionhaving an A. P. L gravity above 9, a viscoslty index between about -100and about +50 and having a viscosity at 100 F. of between about 1000 andabout 5000 Saybolt seconds and between about 75 and about parts of amin- 20 eral oil fraction, said mixture being sulphurized by the actionof an elemental sulphur in an amount of between about 1 and about 10% byweight at a temperature between about 300 and I about 375 F. iollowed byrapid cooling to below 250 F. E

7. A composition of matter as in claim 6 to which has been a fatty oilprior to the sulphuriion.

8. A composition of matter as in claim 6 to 30 which has been added asmall amount 01 a pour point depressant and a soluble lead soap takenfrom the group consisting of lead naphthenate and lead sulphonate.

9. A composition oi! matter as in claim 6 to 35 which is added betweenabout 3 and about 15% of a soluble lead soap selected from the groupconsisting oi lead naphthenate and lead sulphonate.

JOHN C. ZIMMER. 40

